The present invention relates to a video phone which adjusts an image display, volume output, and illumination lighting.
To display the user's face at a proper size on the display of the partner's video phone during telephone conversation with the partner through the video phone, the distance between the user's face and a camera attached to the video phone must be kept constant.
A volume output from the loudspeaker is kept constant regardless of the distance between the user and the video phone. To listen to the partner's voice at an appropriate volume, the user must manually adjust the volume.
When the user's environment is dark, the image of the user that is transmitted to the partner's video phone becomes dark.
Reference 1 (Japanese Patent Laid-Open No. 2002-165192) discloses a video phone apparatus which always generates proper video information regardless of the peripheral brightness of an object, and always effectively operates the video transmitting function. The object is illuminated by emitting light from an “infrared LED” in the image sensing range of a camera. However, cost performance decreases when the infrared LED is mounted on a cell phone having the video phone function. The design may be impaired in consideration of the balance with another part which forms the video phone apparatus.
Reference 2 (Japanese Patent Laid-Open No. 2-119390) discloses a video phone set which can take a picture at a contrast improved for a higher brightness even when a picture is taken in a dark room or an object to be photographed is illuminated from behind, and can synchronize illumination with the use of the video phone set. However, as shown in FIG. 2 of reference 2, the illumination unit of the video phone set targets a very wide range, and cost performance decreases. The design may be impaired in consideration of the balance with another part which forms the video phone set.
Reference 3 (Japanese Patent Laid-Open No. 2004-40491) discloses a video communication equipment capable of improving usability. The contour of the face of a user to be photographed is determined via a CCD camera in accordance with the image sensing distance. The zoom ratio is automatically controlled on the basis of the determined contour so that the user's face falls within the view angle of the CCD camera. The user's face is displayed at an optimal size on the display. The reference volume output level is increased in accordance with the automatically changed zoom ratio, and an optimal image desirable for the communication partner can be obtained.
However, the method of displaying the user's face at an optimal size is not limited to determination of the face contour. For a display at an optimal size, it is more important to adjust the zoom ratio and properly display the user's face, than to determine the face. Considering matching with the user's face displayed on the display, the volume output is preferably adjusted on the basis of the distance between the camera and the user, instead of the zoom ratio.
Reference 4 (Japanese Patent Laid-Open No. 2003-230049) discloses a camera control method and the like which employ a smaller number of audio input units and can eliminate the influence of peripheral echo and display an accurate face image of a speaker on the screen. The face image of the speaker is automatically adjusted to an appropriate size by zooming. Reference 4 pertains to an invention of a camera used in a video conference system. In order to photograph a speaker, the orientation and position of the camera can be properly changed. When the camera is mounted on a video phone, cost performance decreases. For a display at an optimal size, it is more important to adjust the zoom ratio and properly display the user's face, than to detect a face image.